1. Field of the Invention
The invention relates to a flat heat pipe and a method of manufacturing the same and, more particularly, to a flat heat pipe with a capillary structure and a method of manufacturing the flat heat pipe, wherein the interior of the capillary structure is thin and the exterior of the capillary structure is thick.
2. Description of the Prior Art
Heat dissipating device is a significant component for electronic products. When an electronic product is operating, the current in circuit will generate unnecessary heat due to impedance. If the heat is accumulated in the electronic components of the electronic product without dissipating immediately, the electronic components may get damage due to the accumulated heat. Therefore, the performance of heat dissipating device is a significant issue for the electronic product.
So far the heat dissipating device used in the electronic product usually consists of a heat pipe, a heat dissipating fin and a heat dissipating fan, wherein one end of the heat pipe contacts the electronic component, which generates heat during operation, the other end of the heat pipe is connected to the heat dissipating fin, and the heat dissipating fan blows air to the heat dissipating fin so as to dissipate heat. In general, the heat pipe mainly comprises circular heat pipe and flat heat pipe. The flat heat pipe mainly consists of a flat hollow pipe, a capillary structure and a working fluid. The conventional capillary structure is usually formed on an inner wall of a circular hollow pipe by a metal powder sintering process and then the circular hollow pipe is compressed to form the flat heat pipe. In general, if a wall thickness of a heat pipe is smaller than 2 mm, the heat pipe is called “ultra-thin heat pipe”, and if a wall thickness of a heat pipe is larger than 2 mm, the heat pipe is called “thin heat pipe” . However, no matter how the heat pipe is thinned, the heat pipe still has to reserve enough inner space for the working fluid to change between liquid state and gaseous state. Since the capillary structure occupies much more inner space of the heat pipe except the working fluid, how to effectively make use of limited inner space of the heat pipe (especially the thin or ultra-thin heat pipe) has become a significant design issue.